The U.S. attorney's office said John Melvin Walker of San Clemente was one of 14 people named in a federal indictment in October following an investigation by the Orange County Sheriff's Department, the Internal Revenue Service and other agencies.

Walker, 56, entered a guilty plea to one count of conspiring to distribute over a ton of marijuana and to maintaining drug-involved premises. He also pleaded guilty to a tax evasion count in a second case that was filed in February.

Walker admitted in the federal tax case that he earned approximately $25 million from marijuana sales over the course of six years. In 2009, Walker earned $11.4 million but reported income of only $200,180.

Walker also said that he directed the managers of his shops to shred records as part of his effort to conceal income from tax authorities.

For the tax years 2006 through 2011, Walker agreed to pay the IRS more than $2.4 million, as well as $1.8 million in restitution to the California Board of Equalization. He also agreed to forfeit $25 million in illegally obtained income, which includes, among other assets, cash, his $1.7 million home in San Clemente, a string of mobile homes in Mammoth Lakes, rental properties in Long Beach and his interest in two strip clubs.

Walker has two prior felony drug-trafficking convictions from state court.

The remaining defendants in this case are scheduled to go on trial in September.